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A low complexity method of resource allocation in up-link macrodiversity systems using long-term power.Chen, Yu-An January 2013 (has links)
Macrodiversity system is a communication architecture where base stations (BS) act as distributed nodes of a multiple-input multiple-output (MIMO) antennas. It has many promising features that can improve system performance from a network perspective, such as improving the weak signals of users affected by shadow fading, or users at the cell-edge.
They also allow multiple users to share the same resource in time and frequency, improving the overall user capacity.
Traditionally, evaluating the link quality of resource-sharing users requires instantaneous channel state information (CSI). However, finding compatible users to share resource in
macrodiversity systems is a challenging task. For macrodiversity systems, instantaneous CSI could be passed to the backhaul processing unit (BPU) through the network backhaul. This creates a delay in the signal, and makes instantaneous CSI a less accurate reflection of the channel environment at the time. Passing instantaneous CSI of all users also creates a significant amount of network overheads, reducing the overall efficiency of the network. Compared to MIMO systems with co-located antennas, macrodiversity systems cover a larger geographical area and more users. For this reason, the number of user selection combinations can become extremely large, making scheduling decisions in real time an even more challenging task. These problems limit the realisation of the user capacity potential of macrodiversity systems.
This thesis presents a low complexity method of resource allocation for up-link macrodiversity systems. In particular, it uses long-term power to estimate the link quality of resource-sharing users. Using long-term power bypasses the issue of channel estimation error introduced by the network delay, and it also reduces the communication overhead on the network backhaul. In this thesis, we use Symbol-Error Rate (SER) as the measure for link quality. Using the method developed by Basnayaka [1], we are able to estimate SER of resource-sharing users using long-term power. Using the SER estimation method, we further proposed a user compatibility check (UCC), which evaluates the compatibility of users sharing the same resource. Users are only considered compatible with each other if all of them meet a pre-defined SER threshold.
We attempt to reduce the complexity of user selection by using heuristic solution-finding methods. In our research, we found that greedy algorithms have the least complexity. We
propose four low-complexity user selection algorithms based on a greedy algorithm. These algorithms are simulated under different environment parameters. We evaluate the system
performance in terms of utilisation and complexity. Utilisation refers to the percentage of allocated users compared to the theoretical user capacity. Complexity refers to the number
of SER calculations required to find a resource allocation solution. From the simulation results, we observed that with the proposed user selection algorithms, we can achieve
moderately high utilisation with much lower complexity, compared to finding user selections via an exhaustive search method. Out of the proposed user selection algorithms, the
Priority Order with Sequential Removal (PO+SR) and the First-Fit (FF) algorithm have the best overall performance, in terms of the trade-off between utilisation performance, and
complexity performance. The final choice of the algorithm will depend on the processing power and the system performance requirement of the macrodiversity system.
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Message processing of evidence and long-term retention and judgment of beliefs.Baesler, Erland James. January 1991 (has links)
This communication study investigated characteristics of evidence that influenced memory and beliefs about juvenile delinquency across multiple time periods. Four hypotheses were proposed: (H1) vivid evidence is more memorable than nonvivid evidence, (H2) story evidence is more memorable than statistical evidence, (H3) vivid evidence is more persuasive than nonvivid evidence after 48 hours, but not after one week, and (H4) story evidence is more persuasive than statistical evidence after 1 week, but not after 48 hours. A 2 x 2 x 3 factorial design with an offset control was employed, using evidence (story or statistical), vividness (vivid or nonvivid), and time (immediate, or 48 hour delay, or 1 week delay) as independent variables, and recognition memory and judgment of belief as dependent variables. Four written messages, reflecting a complete crossing of evidence and vividness, were used as different types of evidence to attempt to persuade beliefs. A total of 280 undergraduate college students participated in the experiment. Hypotheses 1 and 2 were supported by main effects for vividness and evidence, and by a significant ordinal two-way interaction between vividness and evidence such that vivid story was the most memorable form of evidence. The two-way interactions used to test Hypotheses 3 and 4 were nonsignificant. A main effect for evidence related to Hypothesis 4 indicated that statistical evidence was more persuasive than story evidence at the delayed time periods. Thus, Hypotheses 3 and 4 were not supported. Alternative explanations were discussed to account for the persuasiveness of statistical evidence and the lack of persuasiveness of story evidence at the delayed time periods. Limitations of the study were noted, such as the small amount of experimental variance accounted for in some of the findings, and the limited generalizability of the findings. Finally, several suggestions for future research, including reconceptualizing evidence as a multidimensional construct, were presented.
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An improved error correction algorithm for multicasting over LTE networks / Johannes Mattheus CorneliusCornelius, Johannes Mattheus January 2014 (has links)
Multicasting in Long-Term Evolution (LTE) environments poses several challenges if it is to be reliably implemented. Neither retransmission schemes nor Forward Error Correction (FEC), the traditional error correction approaches, can be readily applied to this system of communication if bandwidth and resources are to be used efficiently. A large number of network parameters and topology variables can influence the cost of telecommunication in such a system. These need to be considered when selecting an appropriate error correction technique for a certain LTE multicast deployment. This dissertation develops a cost model to investigate the costs associated with over-the-air LTE multicasting when different error correction techniques are applied. The benefit of this simplified model is an easily implementable and fast method to evaluate the communications costs of different LTE multicast deployments with the application of error correction techniques. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
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Long-term abnormal stock performance : UK evidenceHuang, Yan January 2012 (has links)
One of the most controversial issues for long-term stock performance is whether the presence of anomalies is against the efficient market hypothesis. The methodologies to measure abnormal returns applied in the long-run event studies are questioned for their reliability and specification. This thesis compares three major methodologies via a simulation process based on the UK stock market over a period of 1982 to 2008 with investment horizons of one, three and five years. Specifically, the methodologies that are compared are the event-time methods based on models (Chapter 3), the event-time methods based on reference portfolios (Chapter 4), and the calendar-time methods (Chapter 5). Chapter 3 covers the event-time approach based on the following models which are used to estimate normal stock returns: the market-adjusted model, the market model, the capital asset pricing model, the Fama-French three-factor model and the Carhart four-factor model. The measurement of CARs yields misspecification with higher rejection rates of the null hypothesis of zero abnormal returns. Although the application of standard errors estimated from the test period improves the misspecification, CARs still yield misspecified test statistics. When using BHARs, well-specified results are achieved when applying the market-adjusted model, capital asset pricing model and Fama-French three-factor model over all investment horizons. It is important to note that the market model is severely misspecified with the highest rejection rates under both measurements. The empirical results from simulations of event-time methods based on reference portfolios in Chapter 4 indicate that the application of BHARs in conjunction with p-value from pseudoportfolios is appropriate for application in the context of long-run event studies. Furthermore, the control firm approach together with student t-test statistics is proved to yield well-specified test statistics in both random and non-random samples. Firms in reference portfolios and control firms are selected on the basis of size, BTM or both. However, in terms of power of test, these two approaches have the least power whereas the skewness-adjusted test and bootstrapped skewness-adjusted test have the highest power. It is worth noting that when the non-random samples are examined, the benchmark portfolio or control firm needs to share at least one characteristic with the event firm. The calendar-time approach is suggested in the literature to overcome potential issues with event-time approaches like overlapping returns and calendar month clustering. Chapter 5 suggests that both three-factor and four-factor models present significant overrejections of the null hypothesis of zero abnormal returns under an equally-weighted scheme. Even for stocks under a value-weighted scheme, the rejection rate for small firms shows overrejection. This indicates the small size effect is more prevalent in the UK stock market than in the US and the calendar-time approach cannot resolve this issue. Compared with the three-factor model, the four-factor model, despite its higher explanatory power, improves the results under a value-weighted scheme. The ordinary least squares technique in the regression produces the smallest rejection rates compared with weighted least squares, sandwich variance estimators and generalized weighted least squares. The mean monthly calendar time returns, combining the reference portfolios and calendar time, show similar results to the event-time approach based on reference portfolios. The weighting scheme plays an insignificant role in this approach. The empirical results suggest the following methods are appropriately applied to detect the long-term abnormal stock performance. When the event-time approach is applied based on models, although the measurement of BHARs together with the market-adjusted model, capital asset pricing model and Fama-French three-factor model generate well-specified results, the test statistics are not reliable because BHARs show severe positively skewed and leptokurtic distribution. Moreover, the reference portfolios in conjunction with p-value from pseudoportfolios and the control firm approach with student t test in the event-time approach are advocated although with lower power of test. When it comes to the calendar-time approach, the three-factor model under OLS together with sandwich variance estimators using the value-weighted scheme and the mean monthly calendar-time abnormal returns under equal weights are proved to be the most appropriate methods.
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On the long-term equilibrium of mortality rates among multiple populationsXing, Guangyu 24 June 2016 (has links)
As human life expectancy continues to increase, longevity risk has become a major concern for pension plan sponsors and annuity providers. To hedge the risk, longevity-linked securities have been developed. Since these securities often have payoffs linked to mortality rates of multiple populations, it is important to investigate the relationship between them. In this thesis, we use England and Wales (EW) and Canadian mortality data for illustration. We consider the long-term equilibrium between the mortality indexes of the two populations through cointegration analysis. Our test shows that structural change occurred in the equilibrium. To capture changes in both equilibrium and autoregression structure, we adopt the Threshold Vector Error Correction Model (TVECM). We find that the TVECM model provides adequate fit to our data. This model is further applied to pricing an illustrative longevity bond. Our numerical results indicate that the changes in the long-term equilibrium have a significant impact on longevity bond prices. / October 2016
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The Role of Regulation in the Care of Older People with Depression Living in Long-Term Care in OntarioCrick, Michelle 29 April 2019 (has links)
In this thesis, the overall purpose was to investigate the role of regulation in the care of older people with depression living in long-term care (LTC).
The first manuscript in this thesis is a systematic scoping review protocol which was published in BMJ open, using Arksey and O'Malley's scoping review methodology as a guide. In the second manuscript which was submitted to BMC Geriatrics, a systematic scoping review was conducted, exploring the concepts of regulation, older people, depression, and long-term care. The search yielded 778 unique articles, of which 21 were included in the final analysis. The scoping review revealed that the highly regulated environment of LTC poses significant challenges which can influence the quality of care of residents with depression. Despite evidence of high prevalence and improved treatment, regulation appears to have failed to capture best practice and contemporary knowledge. The scoping review demonstrated a need for further empirical research to explore these issues.
Findings from this study, which explored the role of regulation on the quality of care of older people living with depression in LTC are presented, and which were the basis of the third manuscript, to the Canadian Journal of Aging. Using instrumental case study methodology, I interviewed managers, staff, informal carers and residents, and reviewed documents and clinical charts. I found that Ministry of Health and Long-Term Care regulations influenced strategic planning, educational priorities, resourcing decisions and direct care. The findings from the study suggest an alternative approach to regulation is needed in this sector, which places accountability for standards of care at a provincial level and which has a more supportive and collaborative approach to regulations. The research findings showed that the staff working in the LTC home are committed to the care of residents with depression, but they had little time to implement additional quality initiatives outside of the identified mandated areas. The study concludes by suggesting that in its current state, the care of residents with depression in LTC homes is not reflected in Ministry of Health and Long-Term Care regulations and inspections, which make little difference to the care of older people living with depression living in LTC.
In contributing to the existing knowledge and practice the study along with the findings from the scoping review, finds an alternative model of inspection could be implemented in partnership with the province. An alternative approach to inspection might adopt an extended approach to quality, along with an individualized approach to inspections to meet the requirements set out in regulation, but at the same time offering flexibility and a more collaborative approach to improving quality in the LTC sector.
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Long term soft tissue LIP changes following orthodontic treatmentSathekge, Rachel Motshwanetsi 01 November 2006 (has links)
Student Number : 0204056G -
MD research report -
School of Oral Health Science -
Faculty of Health Sciences / Evaluating facial profiles and facial balance is a continuous learning process for orthodontists. Hence, the importance of studying the intermediate and long term effects of treatment on soft tissues cannot be overemphasized.
The objective of this study was to evaluate the lip changes occuring in response to tooth movement, not only immediately post-treatment but also to following the long-term monitoring when cranio-facial growth has ceased. The lip changes were measured relative to the Burstone (B-line) line. The sample was taken from the records successfully treated orthodontic cases in the Department of Orthodontics at the University of the Witwatersrand, Johannesburg. This sample comprised 18 Caucasoid females (14 extracttion, 4 non-extraction). Pre-treatment, post-treatment, and long term follow-up lateral cephalometric radiographs were evaluated.
Statistical evaluation of the lips in the long term follow-up records revealed no statistically significant changes. The lips remained, relatively, in a similar position to that which had been attained immediately post-treatment. This was the case for both the extraction and non-extraction groups.
The general lack of consistency in post-treatment correlations between dental variables and the soft tissue form supports the hypothesis that the soft tissues, having their own inherent architecture, respond independently. This varied response to tooth movement makes lip movement difficult to predict on a reliable basis.
The concept that is better to finish the cases slightly more protrusive because the lips tend to lose elasticity with age and, as a result, become more retrusive, is therfore supported by these observations.
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A Study of Verbal and Action Memory among Athletes and Non AthletesNyberg, Sebastian, Pirmoradi, Ata January 2008 (has links)
No description available.
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Acquiring firm long-term performance and governance characteristicsBreazeale, Jonathan Paul 30 September 2004 (has links)
I examine the market reaction to merger announcements and the long-term post-merger stock price performance of newly merged firms. For a sample of 484 acquiring firms completing mergers between 1993 and 2000, the average value-weighted abnormal announcement date return (market-adjusted) is a statistically significant -1.02%. On average, this reaction is more negative for firms with "good governance." Specifically, a governance index comprised of three governance variables is significantly negative in a multivariate regression of announcement date abnormal returns. Comp is the percentage of CEO salary consisting of equity incentives (including stock options and restricted stock grants), InsideOwn is the percentage of the firm owned by officers and directors, and InstOwn is the percentage of the firm owned by large outside block shareholders. Value-weighted calendar-time portfolios consisting of the full sample of acquirers exhibit significant abnormal returns of 9.12%, 33.84% and 55.8% for the 12, 36 and 60 months following the merger, respectively. This overperformance is limited to the value-weighted portfolios. There is calendar-time evidence of abnormal performance for some subsamples on a risk adjusted basis. However, when compared to a control group, abnormal performance is limited to large glamour acquirers on a 12-month horizon, large cash acquirers on a 36 and 60-month horizon, and small focusing acquirers on a 60-month horizon. Multivariate analysis of long-run returns reveals that use of equity and corporate diversification are associated with lower post-merger performance. With regard to governance and long-run stock returns, there is also evidence that suggests higher levels of incentive compensation for CEOs is associated with more successful merger transactions for long-term investors.
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A Study of Verbal and Action Memory among Athletes and Non AthletesNyberg, Sebastian, Pirmoradi, Ata January 2008 (has links)
No description available.
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